Various enclosures, whether they are sealed, substantially sealed, or unsealed to their surrounding environment are cooled. Typically, the enclosures house various components that may be adversely affected by temperatures elevated above room or ambient temperature. In the case of enclosures containing electrical equipment, heat buildup within the enclosures can damage the components and/or cause safety hazards, for example, fires. Many of these enclosures, particularly those that are substantially or completely sealed, are not easily ventilated.
U.S. Pat. No. 3,654,768, entitled “Vortex Tube Cooling System” (the “'768 patent”) which is hereby incorporated by reference in its entirety, discloses a cooling system particularly adapted for various types of enclosures, including sealed, substantially sealed, and unsealed enclosures. The system disclosed in the '768 patent is a vortex tube cooling system that includes a mechanical thermostat operable to actuate a valve that controls the flow of compressed air to the vortex tube, which, in turn, controls the temperature inside the enclosure. The embodiments described in the '768 patent provide a relatively small, thermostatically controlled cooling system that is easy to install and requires relatively low maintenance, when compared to conventional “Freon type” air conditioners. The systems disclosed in the '768 patent, however, provide a cooling system that produces high noise levels. In particular, the noise created by the high velocity spinning air within a vortex tube may be objectionable to some. Such noise may annoy, irritate, or even cause discomfort to, an operator of the enclosure, or those in close proximity to the enclosure.
Previous attempts at minimizing noises produced by the vortex tube include attaching mufflers to the hot and cold ends of the vortex tube. The mufflers, however, do not substantially reduce the noise levels a significant amount.
U.S. Pat. No. 7,461,513, entitled “Cooling System” (the “'513 patent”) which is hereby incorporated by reference in its entirety, discloses a compact cooling system that is easy to install and produces low noise levels. The system disclosed in the '513 patent has a single cooling device, which results in a limited cooling capacity of the system.
U.S. Pat. No. 5,010,736, entitled “Cooling System for Enclosures” (the “'736 patent”) discloses a two-stage enclosure cooler. The system disclosed in the '36 patent employs two different types of cooling. The first stage of cooling is a simple air-to-air heat exchange and the second stage is a vortex tube cooler. In the system described in the '736 patent, the first stage heat exchanger operates continuously, never shutting off. Because its first stage cooler is a heat exchanger (and not an ‘active’ cooling device), temperatures inside the enclosure used with the system may never be cooled below the ambient temperature conditions.
Thus, a need exists for a cooling system having a substantial cooling capacity that is also easy to install and produces low noise levels.
There is a further need or desire for a cooling system that allows for reduced compressed air consumption during periods of low heat load.